Mathematical processes in the brain influenced by language

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Published on Thursday, 14 September 2017

People can intuitively recognise small numbers up to four, however when calculating they are dependent on the assistance of language. In this respect, the fascinating research question ensues: how do multilingual people solve arithmetical tasks presented to them in different languages of which they have a very good command? This situation is the rule for students with Luxembourgish as their mother tongue, who were first educated in German and then attended further schooling in French as teaching language.

This question was investigated by a research team led by Dr Amandine Van Rinsveld and Professor Christine Schiltz from the Cognitive Science and Assessment Institute (COSA) at the University of Luxembourg. For the purpose of the study, the researchers recruited subjects with Luxembourgish as their mother tongue, who successfully completed their schooling in the Grand Duchy of Luxembourg and continued their academic studies in francophone universities in Belgium. Thus, the study subjects mastered both the German and French languages perfectly. As Luxembourger students, they took maths classes in primary schools in German and then in secondary schools in French.

In two separate test situations, the study participants had to solve very simple and a bit more complex addition tasks, both in German and French. In the tests, it became evident that the subjects were able to solve simple addition tasks equally well in both languages. However, for complex addition in French, they required more time than with an identical task in German. Moreover, they made more errors when attempting to solve tasks in French.

The bilingual brain calculates differently depending on the language used

During the tests, functional magnetic resonance imaging (fMRI) was used to measure the brain activity of the subjects. This demonstrated that, depending on the language used, different brain regions were activated.

With addition tasks in German, a small speech region in the left temporal lobe was activated. When solving complex calculatory tasks in French, additional parts of the subjects’ brains responsible for processing visual information, were involved. During the complex calculations in French, the subjects additionally fell back on figurative thinking. The experiments do not provide any evidence that the subjects translated the tasks they were confronted with from French into German, in order to solve the problem.

While the test subjects were able to solve German tasks on the basis of the classic, familiar numerical-verbal brain areas, this system proved not to be sufficiently viable in the second language of instruction, in this case French. To solve the arithmetic tasks in French, the test subjects had to systematically fall back on other thought processes, not observed so far in monolingual persons.

The study documents for the first time, with the help of brain activity measurements and imaging techniques, the demonstrable cognitive “extra effort” required for solving arithmetic tasks in the second language of instruction. The research results clearly show that calculatory processes are directly affected by language.

For the Luxembourg school system, these findings are somewhat groundbreaking, given the well-known fact that, upon moving from primary school to secondary school, the language of instruction for math changes from the primary teaching language (German) to the secondary teaching language (French). This is compounded by the fact that a much smaller proportion of today’s student population in the Grand Duchy has a German-speaking background compared to previous generations, and it can be assumed that they already have to perform visual translation tasks in German-speaking math classes in primary school.